Document retrieval in an enterprise setting can be a very important issue, particularly when one wishes to find critical information in a timely manner. For example, in a healthcare setting, it may be useful to find relevant alternate cases for a case that a doctor is currently working on, such as to find a pattern and/or particular treatment. As an example, the doctor may be interested in finding previous patients who are both smokers and have allergy to aspirin. Typically, document searching involves keyword searching where a relevant word that may be found in a document is input to a search engine, and those documents that comprise the keyword are retrieved. Document retrieval can be performed on an enterprise database, such as a hospital, a distributed database, and online resources, such as the Internet.